Effect of castration and gonadal hormones on insulin-induced drinking.
Female Wistar rats in any of the estrual phases have been shown to drink significantly more water than males (p < 0.05), after a single I.P. insulin injection (5 U/kg b.wt.). Sexual differences in insulin-induced drinking persisted after castration when it was made in adult rats (4.6 +/- 1.2 ml/2 h, males = 8; vs. 13.0 +/- 3.1 ml/2 h, females = 8; p < 0.05). On the other hand, when animals were castrated before puberty or when newborn, sexual differences in insulin-induced drinking disappeared. Hence, insulin-induced drinking seems to be a sex-dependent phenomenon that differentiates just before or during puberty since it is abolished by castration prior to sexual maturation. Sex hormone administration in male and female rats castrated at different ages showed a variety of actions on insulin-induced drinking. A pattern emerged showing that androgenized (testosterone treated) rats drank usually less in response to insulin than estrogen-treated rats (independent of their genetic sex). According to the above results, we can conclude that insulin-induced drinking is a phenomenon sensible to gonadal hormones, both by conditioning the differentiation of some physiological structure or mechanisms that underlay drinking behavior in that paradigm and by a direct action on these or other related mechanisms.
Fernández-Trisac
J L
JL
Departamento de Biología Funcional, Facultad de Medicina, Universidad de Oviedo, Spain.
Brime
J I
JI
López-Sela
P
P
Sánchez-Garrido
L
L
Costales
M
M
Argüelles
J
J
Vijande
M
M
D000818:Animals; D002369:Castration; D004326:Drinking / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D007004:Hypoglycemic Agents / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology*; D008297:Male; D009919:Orchiectomy; D010052:Ovariectomy; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology
D012739:Gonadal Steroid Hormones; D007004:Hypoglycemic Agents; D007328:Insulin; D013739:Testosterone; D004958:Estradiol